It’s made of brass

I’ve uploaded another photo of the only thing I can find on the Internet of it and it’s very brief they don’t know anything about it either but it’s the only one in the world that I can find

Thanks, Tim, for confirming the material and the additional photograph. I've found two other examples of a Martin's patent self-canting anchor having been offered at auction and the links (and prices realized) are below:
($1500) https://www.invaluable.com/auction-lot/martins-self-canting-cased-anchor-and-chain-patent-214-c-086447a9ae
(£60)https://www.invaluable.com/auction-lot/a-martins-patent-self-canting-anchor-the-brass-bo-469-c-47540e0d21

I would value yours at $800-1,200; if you want to sell it, I would strongly recommend selling it at an auction house that specializes in maritime / marine antique sales.

Martins patent self canting anchor
Brass, 12 1/2 inches long, 5 1/2 inches wide
Engraved "Tested at the Royal dockyard and at Lloyd’s proving machines 50 per cent over the Admirality proof without Deflection The only anchor without welding As supplied to the English French Persian and American governments and the Mercantile Navy"
$800-1200*
*represents a fair-market value for auction purposes; retail or asking price may vary.